Carlos and Clara, the peregrine falcon parents living atop San Jose City Hall, are expected to make quite a fuss when their three babies’ legs are banded on May 16 so that scientists can identify them after they fly off.

“If it’s anything like last year, they’ll be actively defending their nest, flying in big circles, with this incredibly loud cakking, shrieking and dive bombing, said mayoral spokeswoman Michelle McGurk. “We’re going to have staff nearby with hard hats on.”

McGurk said the best spot for watching as University of Santa Cruz Predatory Bird Research Group field biologist Brian Latta rappels down onto City Hall’s nest box ledge will be at the back of the building on Fifth Street off San Fernando Street.

Latta will begin his work about 11:30 a.m., and return to reveal the genders of the three baby falcons born April 22. The young birds are expected to fly off two to three weeks later.

Latta plans to bring down the remaining unhatched egg, which scientists now think was unfertilized. Santa Cruz scientist Janet Linthicum said she hopes her predatory bird researchers can test that egg for environmental contaminants including flame retardants, which were found in peregrine falcon eggs in San Francisco, Long Beach, Los Angeles, and San Diego, according to a study by the California Environmental Protection Agency’s Environmental Chemistry Laboratory.

Last year, all the San Jose falcons hatched so there were no eggs to test, Linthicum said.

McGurk said falcon fans can also perch on other good spots to watch the banding: on top of the Fourth Street garage, or in the Bamboo Garden at City Hall.

Of course, if you can’t leave work, or live too far away, anyone can click on www.scpbrg.org to get streaming video of the nest box from the webcam that’s been affixed near the bird’s home.

When the eggs were laid in February, McGurk said the average daily visits to the city’s Web site linking to the falcon webcam was 1,449. After the falcon eggs hatched, that number soared to an average of 18,056 visits a day, McGurk said.

May 16 is also the contest deadline for school-age kids to name the three baby birds. The winners will be announced a few weeks later.